JPH02181068A - Fuel feeder for internal combustion engine - Google Patents

Abstract

PURPOSE: To keep pressure differential constant by solving pressure differential of a first input that is a function of pressure in fuel path and a second input that is a function of pressure in intake manifold, and controlling the rate change of a fuel pump corresponding to the pressure difference. CONSTITUTION: A fuel delivery system has an electric motor fuel pump 12 arranged in a fuel tank 14 for supplying fuel under pressure to a fuel path 18 through a fuel line 16, and the remainder of the fuel returns back the tank 14 through return line 20, 22 and a one way valve 24. Injectors 26 to 32 are arranged in an intake manifold 34 in correspondence with each cylinder. In this invention, a pressure differential sensor 46, for receiving the first input that is a function of pressure in the fuel path 18 and the second input that is a function of pressure in the intake manifold 34 and solving the pressure differential, is arranged. The electric motor of the fuel pump 12 is driven and controlled by the output of the sensor through a pulse duration modulator- amplifier 48.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a fuel delivery system for an internal combustion engine, and more particularly to a fuel delivery system for an internal combustion engine, including at least one fuel injector located between a pressurized fuel supply and an intake manifold of the engine. Concerning what is suitable for fuel injection devices.

[Prior art and problems to be solved by the invention] In the case of a fuel delivery device for an internal combustion engine having a conventional structure, fuel is delivered from the fuel tank to the engine by a metering delivery pump, and excess fuel is sent from the engine to the fuel tank. return. This returned fuel transfers engine heat to the fuel supply, thereby increasing the temperature and vapor pressure of the fuel supply. Not only does the release of excess vapor pressure into the atmosphere create pollution problems, but it also has a negative impact on fuel efficiency.

Excess temperature in the fuel tank can cause the pump to swell, especially when the fuel level is relatively low. Similarly, constant operation of the pump increases energy consumption and shortens the life of both the pump and the fuel filter.

In the case of a fuel injection system for an internal combustion engine, as disclosed in U.S. Pat. Excess fuel returns to the supply tank as a function of the pressure differential between the fuel passageway and the engine intake manifold. A plurality of fuel injectors are installed between the fuel passage and the intake manifold of the engine, and in this case, the nozzle of the injector is installed adjacent to the fuel or air intake bow 1- of each cylinder of the engine. It is being 1 filed by the applicant
U.S. Pat. No. 4, 789,308, dated December 6, 988.
In the case of the fuel delivery system for an internal combustion engine disclosed in the above publication, the outlet pressure of the electric fuel pump is monitored and the pump motor current is controlled as a function of the outlet pressure.

The fuel delivery devices disclosed in the above patents and applications include:
Since there are the above-mentioned problems regarding the structure, further improvement is desired.

Therefore, it is an object of the present invention to maintain a constant differential pressure in a fuel delivery mechanism, in particular a fuel injector, and to maintain a constant amount of fuel supplied during the injector operating time, independent of pressure fluctuations in the intake manifold. It is an object of the present invention to provide a fuel delivery device suitable for a fuel injection device of the disclosed type.

Another object of the invention is to provide a differential pressure control device with the above characteristics that is economical in mass production, such as for example in automotive fuel delivery systems, and is reliable over a long period of time, as long as the life of the vehicle. Another object of the present invention is to provide a fuel delivery device which, in addition to the above-mentioned features, is characterized by delivering fuel as needed, thereby reducing energy consumption and increasing the operating life of the pump and fuel filter. It is to provide.

Yet another object of the present invention is to provide a fuel delivery system characterized in that less engine heat is transferred to the fuel tank, thereby eliminating the problems associated with fuel vaporization mentioned above. Still yet another object of the invention is to provide a fuel delivery system for electronically controlling a fuel pump as a function of fuel requirements, characterized in that the control electronics are cooled by the fuel circulating through the delivery system. That's true.

(Means for Solving the Problems) In order to achieve the above object, a fuel delivery device for an internal combustion engine according to the present invention includes a fuel supply source having a fuel pump responsive to electric power used to deliver fuel by pressurization. an air intake manifold of an engine including a device for supplying combustion air to the manifold; a fuel delivery device coupled to the fuel source to control fuel delivery from the source to the manifold; and power to the pump. a power supply device for an internal combustion engine, the power supply device having a first input portion coupled to the fuel supply source and responsive to pressure of fuel delivered to the fuel delivery device; a second input coupled to the engine manifold and responsive to air pressure within the manifold;
and an output for transmitting an electrical sensor signal that varies as a direct continuous function of the differential pressure between the inputs of and a second; and in response to said signal, as a continuous inverse function of said differential pressure. The present invention is characterized by having a device that maintains the differential pressure of the fuel delivery device substantially constant by supplying power to the pump and controlling speed changes of the pump.

[Effect]

A fuel delivery system for an internal combustion engine according to the present invention includes a fuel supply having an electric fuel pump that delivers pressurized fuel in response to applied electrical power. An air intake manifold of the engine supplies combustion air to each cylinder of the engine, and at least one fuel injector is connected between the fuel supply and the intake manifold. The pressure sensor mechanism, preferably an integrated differential pressure sensor, is responsive to the pressures of the fuel injectors and the intake manifold of the engine and generates an electrical signal that varies as a function of these differential pressures.

Electric fuel pumps are operated as a function of such differential pressure, and DC power, preferably pulsed by a pulse width modulated amplifier, is applied to the motor at a constant frequency and in a duty cycle that varies as a function of the differential pressure signal. Supplied. In this way, the fuel pressure in the injector is automatically controlled to maintain a constant pressure differential in the injector between the fuel passage and the engine intake manifold, reducing the amount of circulating fuel and thus reducing the amount of fuel in the injector. The amount of engine heat transferred to the tank is reduced and the fuel delivery pump is operated as a function of the fuel required.

In a preferred embodiment of the invention, the pump control electronics, which may of course be either digital or analog, are mounted on a printed wiring board. The circuit board is attached to a body of thermally conductive material having passageways for delivering circulating fuel so that the circulating fuel removes heat from the pump-driven electronics to effectively cool the equipment. A check valve is provided in the fuel return line to retain fuel in the injector when the pump is not operating. According to one embodiment of the invention, the check valve is mounted in a passage extending into the heat absorbing body of the electronic device.

The body is provided with a fuel pressure car pulse damping device formed by a chamber provided with a diaphragm which opens on one side into the fuel passage.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a fuel delivery system 10 according to one preferred embodiment of the present invention, which delivers pressurized fuel via a fuel line 16 to a fuel passage 18 of an engine (not shown). As such, it includes an electric motor fuel pump 12 disposed within a fuel tank 14. Excess fuel in the fuel passage 18 is removed from the return line 20.22 and the fuel passage check valve 2.
4 and return to tank 14. Check valve 24 retains fuel within fuel passage 18 when the motor is at rest, ie, when the engine is stopped. Between the fuel passage 18 and the engine air intake manifold 34 carried by the engine, a plurality of fuel injectors 26 are provided as fuel injection devices serving as fuel delivery devices.
, 28, 30, 32 are installed, and the nozzles of the fuel injectors 26-32 are connected to the fuel or air intake ports for cooperation with the cylinders of the engine.
36-42. The fuel delivery system 10 thus far described is disclosed in U.S. Pat. No. 4,649, discussed above.
, No. 884.

Combustion air is fed to the intake manifold 34 at atmospheric pressure through an air filter or the like, or pressurized by a turbocharger driven by the engine or the like, depending on engine operation, throttle demands, and the like. The fuel injectors 26-32 can be operated by solenoids, for example, by an engine control computer provided in the engine (not shown).

According to the invention, differential pressure sensor 46 receives a first human force as a function of the pressure within fuel passage 18 and a second human force as a function of the pressure within intake manifold 34 . Such input signals may also be derived from other suitable pressure delivery mechanisms. Differential pressure sensor 46 generates an electrical signal as a function of the differential pressure between fuel passage 18 and intake manifold 34. Such differential pressure electrical signal is sent to pulse width modulation amplifier 48 in the form of an analog signal in the embodiment of FIG. The amplifier 48 also receives DC power from the vehicle's electrical system and outputs a pulse signal 50 to operate the electric motor of the fuel pump 12. The pulse output signal of amplifier 48 is preferably provided at a constant frequency and with a duty cycle that varies as a function of the differential pressure signal from differential pressure sensor 46, preferably inversely in time.

When the pressure differential between fuel passage 18 and intake manifold 34 is low, such as during fuel-intensive engine acceleration operations, the duty cycle of signal 50 is high. Therefore, the average DC power applied to the fuel pump 12 will be higher and the pump will operate with this power. On the other hand, the fuel passage 18 and the intake manifold 34
If the pressure difference between the two is high, that is, the engine is idling and requires little fuel, the duty cycle of the amplifier output will be correspondingly low and the fuel pump will operate at a low level.

FIG. 2 shows the electronics controlling the pump, including a differential pressure sensor 46 and an amplifier 48 printed on a body 54 constructed of a thermally conductive material such as stainless steel. It is attached to the wiring board assembly 52. Body 54 has a passageway 56 extending therethrough, including an inlet opening 58 for receiving fuel from fuel pump 12 and an outlet opening 60 communicating with fuel passageway 18 (FIG. 1). It has Thus, since the body 54 is connected in series with the fuel line 16 as shown in FIG. 1, the fuel circulating through the line 16 is effectively cooled by diverting heat away from the pump control electronics. The differential pressure sensor 46 is connected to a main body 54 that communicates with a main fuel passage 56.
the intake manifold 34 (FIG. 1) by means of nipples 64 and hoses 66; Assembly 52 with sensor 46 is fitted with a cover 67 to form a body package 68 .

FIG. 3 shows another example 70 of a control package suitable for installation in the return line 20.22 (FIG. 1) of FIG. 1 between the fuel passageway 18 (FIG. 1) and the fuel tank 14. . The control package 70 has a check valve 24 mounted within the passageway 56 as a flow damping orifice 72 . The cover 74 cooperates with the main body 54 to form a chamber 76, which includes a diaphragm 78 made of stainless steel or the like.
divided by. The upper portion of chamber 76 communicates with fuel passage 56 by port 80 . The lower part of the chamber 76 communicates with the atmosphere through an orifice 82 in the cover 74. Therefore,
Diaphragm 78 serves to dampen pressure changes in the fuel delivery system.

FIG. 4 shows an embodiment 84 in which a microprocessor is used in the pump control electronics. Differential pressure sensor 46 is connected via a differential pressure stage 86 to a microprocessor 88 that is suitably programmed to send a pulse width modulated signal 50 (FIG. 1) to a power amplification stage 90. has been made into pump motor 92
are connected to a power amplification stage 90 to deliver fuel on demand in a dual-direction manner.

FIG. 5 shows another type of fuel delivery system 94 representing another preferred embodiment of the present invention, in which one fuel injector 26 is disposed within a central passage 96 of a throttle body 98. This throttle body 9
8 delivers fuel to the engine's intake manifold 34 via a throttle valve 100. The remainder of the fuel delivery system 94 of FIG. 5 may be the same as the system 10 of FIG. 1.

Although the invention has been described in conjunction with the illustrated preferred embodiment, it will be understood that various modifications may be made without departing from the scope of the invention. For example, instead of differential pressure sensor 46, which is preferably an integrated sensor constructed of silicon or other solid state, it may be of a separate electrical or mechanical type that sends an output to a differential amplifier or the like. Further, for example, a mechanical fuel pump whose output is changed by an electronic solenoid valve may be used as the electric fuel pump. In this case, the pump drive voltage is preferably pulse width modulated as described above, but frequency modulated or direct current or voltage controlled may also be used.

ADVANTAGEOUS EFFECTS OF THE INVENTION Several embodiments of a fuel delivery system have thus been detailed which fully achieve all of the objectives of the invention set forth above. The fuel pump is operated on demand, unlike prior art metering pumps, thereby reducing energy consumption and increasing both the pump life and the operational life of the fuel filter (not shown). Since the fuel pump is operated only when needed, the amount of circulating fuel returned to the fuel tank is significantly reduced and therefore less heat is transferred to the fuel tank. Therefore, problems associated with fuel vaporization are also reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a fuel delivery device showing one of the preferred embodiments of the present invention; FIG. 2 is a sectional view showing an enclosure for mounting pump control electronics of the embodiment of FIG. 1; FIG. FIG. 4 is a schematic electrical diagram of a digital pump control electronic device according to another embodiment of the present invention; FIG. 2 is a schematic diagram of an alternative fuel delivery device according to another preferred embodiment of the invention; FIG. 10.94...Fuel delivery device, 12...Fuel pump, 14...Fuel tank, 16...Fuel line, 18
... Fuel passage, 20.22 ... Fuel return line, 2
4... Check valve, 26.2B, 30.32... Fuel injector, 34... Intake manifold, 3642... Fuel or air intake port, 4
6... Differential pressure sensor, 48... Amplifier, 50... Signal, 52... Printed wiring board, 67.74... Cover, 68... Body package, 78... Diaphragm, 88...Microprocessor, 92...Pump motor.

Claims (14)

[Claims] (1) an engine air intake manifold comprising a fuel supply having a fuel pump responsive to applied electrical power to deliver fuel under pressure; and a device for supplying combustion air to the manifold; In a fuel delivery device for an internal combustion engine, the fuel delivery device includes a fuel delivery device connected to the fuel supply source so as to control fuel delivery up to, and a power feeding device for supplying electric power to the pump, wherein the power feeding device a first input coupled to a source and responsive to the pressure of fuel delivered to the fuel delivery device; a second input coupled to the engine manifold and responsive to air pressure within the manifold; 1st and 2nd
and an output for transmitting an electrical sensor signal that varies as a direct continuous function of the differential pressure between the inputs of the pump; 1. A fuel delivery device for an internal combustion engine, comprising: a device that maintains the differential pressure of the fuel delivery device substantially constant by supplying electricity and controlling speed changes of the pump. (2) the power supply device further comprises a device responsive to the electrical signal for supplying pulse width modulated DC power to the pump at a constant frequency and with a duty cycle that varies as a function of the differential pressure; Claim (1)
A fuel delivery device for an internal combustion engine according to. (3) further comprising a device for returning excess fuel from the fuel delivery device to the supply source, the fuel return device configured to retain fuel in the fuel delivery device when the pump is not in operation; A claim comprising a check valve (
1) The fuel delivery device for an internal combustion engine according to item 1). (4) connecting the fuel supply source and the fuel delivery device;
Claim 1, further comprising a body of thermally conductive material having a fuel passageway extending therethrough, the power supply being mounted to the body such that fuel passing through the body cools the power supply. The fuel delivery device for an internal combustion engine according to (1). (5) a differential pressure sensor in which first and second devices are attached to the main body and have a first input portion that opens into the passage;
5. The fuel delivery device for an internal combustion engine according to claim 4, further comprising a device for connecting the second input portion of the differential pressure sensor to a manifold of the engine. 6. The power supply device further comprises a device for supplying pulse width modulated DC power to the pump at a constant frequency and with a duty cycle that varies as a function of the differential pressure. 5) The fuel delivery device for an internal combustion engine according to item 5). (7) The fuel delivery device for an internal combustion engine according to claim (6), wherein the power supply device including the sensor and the sensor response device further includes a printed wiring board assembly attached to the main body. (8) further comprising a device for returning excess fuel from the fuel delivery device to the supply source, the fuel return device comprising:
Claim (4) further comprising a check valve for retaining fuel in the fuel delivery device when the pump is not in operation.
).) The fuel delivery device for an internal combustion engine. (9) The fuel delivery device for an internal combustion engine according to claim (8), wherein the check valve is disposed within the main body passage. (10) The fuel delivery device for an internal combustion engine according to claim (9), wherein the passage is provided with a fuel flow rate attenuation orifice. (11) The fuel delivery device for an internal combustion engine according to claim (4), wherein the main body is provided with a device for reducing pressure fluctuations when the fuel flows through the passage. (12) The pressure damping device includes a cavity within the main body;
a diaphragm dividing the cavity into a first chamber and a second chamber; a first port connecting the first chamber to the passage; and a second port communicating the second chamber to the atmosphere. The fuel delivery device for an internal combustion engine according to claim (11). (13) Claim (1) characterized in that the fuel delivery device has a fuel passage connected to the pump, and at least one fuel injection device connected between the fuel passage and the manifold. 1) The fuel delivery device for an internal combustion engine according to item 1). (14) The fuel delivery device includes a throttle body having a passage for delivering air to the manifold, and a fuel injection device connected to the pump and attached to inject fuel into the passage. Characteristic claim (1)
A fuel delivery device for an internal combustion engine according to.